External cardial compressor



Jan. 23, 1968 c. E. BANK/@Lowr 3,364,925

EXTERNAL CARDIAC COMPRESSOR Filed Sept. 2, 1965 3 Sheets-Sheet l llllllllllllllllllllllll nlluulmllllllxllll HunfmunuHff/Z/ /l lllllll] ||H||||H|| /25 (ffm ATTORNEYS Jan. 23, 1968 c. E. BARKALOW 3,364,925

EXTERNAL CARDIAC COMPRESSOR Filed Sept, 2, 1965 5 Sheets-Sheet 2 INVENTOR. IJ/M76 i. .B4/ewa md ATTORNEYS Jail 23, 1968 c. E. BARKALOW 3,354.925

EXTERNAL CARDIAC COMPRE S SOR Filed Sept. 2, 3.965v 3 Sheets-Sheet STROKE, //V.

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'BY f A ATTORNEYS United States Patent Oce 3,354,925 Patented Jan. 23, 1968 3,364,925 EXTERNAL CARDIAC COMPRESSOR Clare E. Barkalow, Comstock Park, Mich., assigner to Michigan Instruments, Incorporated, Grand Rapids, Mich., a corporation of Michigan Fiied Sept. 2, 1965, Ser. No. 484,533 9 Claims. (Cl. 12S-53) This invention relates to an external cardiac compressor, and more particularly to a reciprocable cardiac compressor enabling accurate, variable regulation of the compressor stroke to match the specific chest of the patient encountered.

This cardiac compressor is an improvement of the cardiac compressor disclosed in my co-pending patent application entitled Cardiac Compressor, filed Nov. 9, 1964, Serial No. 409,634, and assigned to the assignee herein.

External cardiac compression can be effectively ernployed for obtaining perfusion by causing forced pump` ing of blood from a temporarily stopped heart. This is achieved by constant cyclic external compression of the heart for a short time period (systole), followed by pressure release to allow heart expansion for a short time period (diastole). To achieve proper heart compression by external force, the breastbone is forced toward the backbone, preferably with a portable compact unit capable of use in ambulances, emergency wards and the like, providing a rigid back support for the patient, and having a reciprocable compression plunger.

The importance of a safe, reliable, external cardiac compressor for saving lives is rapidly becoming widely recognized. However, one of the greatest reservations of those knowledgeable persons who have not totally accepted the device involves the potential misuse of the unit by the human operator due to not applying the proper amount of compression. Too little compression can be ineffective. Too much compression can be damaging. Optimum compression, furthermore, varies substantially from person to person. For example, a barrel chested man requires a very different compressive action than a small child. Extensive research has shown that the most significant Variation in compression is the depth of compression. When a iiuid cylinder and plunger type compressor is ernployed, the depth of compression is closely interrelated with and regulated by the amount of pressure applied to the plunger, and hence to the chest.

It is an object of this invention to provide a cardiac compressor having the inherent capacity to indicate to the operator the compression which should be applied to the particular patient. The cardiac compressor itself serves as indicator gauging means.

Another object of this invention is to provide a cardiac compressor enabling the human operator to quickly and accurately determine the depth (or optionally, the pressure) of compressive action to be applied to a particular patient by reference to the same operative components which are necessarily fitted to the patient for cardiac compression. The equipment, when properly oriented and preset for the chest size, automatically indicates the amount of compressive action which should be employed for optimum results.

Another object of this invention is to provide a plunger and cylinder type cardiac compressor having unique calibration on the operating support column that indicates to the operator, when preset for a particular patient, the depth (or optionally, the pressure) to which the compressing plunger should be extended for optimum results.

Another object of this invention is to provide a plunger and cylinder type cardiac compressor having cooperative calibration indicia means associated with both the support column and with the compressor plunger, to enable correlation thereof, for indicating on the column the optimum plunger extension which should be employed, and indicating on the plunger the actual extension being employed.

These and other objects of this invention will become apparent upon studying the following specification in conjunction with the drawings in which:

FIG. 1 is a perspective view of the cardiac compressor shown in a position of use on a patient;

FIG. 2 is a perspective view of the opposite side of the compressor from that illustrated in FIG. l;

FIG. 3 is a sectional view taken on plane IlI-III of FIG. 2, showing the compressor plunger structure;

FIG. 4 is an enlarged plan fragmentary View of the lockable adjustable connection between the compressor arm and support column in the apparatus of FIGS. 1 through 3;

FIG. 5 is a fragmentary perspective exploded view of a releasable connection between the base of the support column and the platform of the apparatus;

FIG. 6 is a side elevational sectional View of the apparatus in FIG. 5;

FIG. 7 is a fragmentary, enlarged, side elevational view of a portion of the support column and arm; and

FIG. 8 is a side elevational, fragmentary, enlarged View of a modified form of the apparatus in FIG. 7.

Referring now specifically to the drawings, the cardiac compressor assembly 10 includes the horizontal base platform subassembly 11, the vertical support column or post 14 extending upwardly from one edge of the rigid platform 12 of subassembly 11, compressor arm 16 extending out over the base plate or platform, and plunger subassembly 18 mounted to the other end of arm 16 over the platform.

The base plate or platform 12 is of rigid metal construction, normally of aluminum. It has a generally fiat upper surface to receive the back of a patient. It provides a rigid, non-flexing support when the patients chest is compressed. It tapers from its thinner outer end to the opposite thicker end 20 of enlarged height. This latter end has a hollow underside to receive the fluid pressure (preferably pneumatic) control system 22 mounted to and housed inside the underside of the unit (FIG. 9), and communicating to the compressor through port connections to be described.

Axed yto the upper surface of this enlarged end portion 20 of platform 12 is a rigid mounting plate 26 having one end extending out over the edge of the platform. This mounting and port connector plate (FIG. 5) has an air line inlet fitting 30 mounted thereon and communieating with a passageway from the fitting to control assembly 22 in a manner to be described. It also has a port 32 extending through the plate and surrounded by an O-ring 34 received in a groove to form a positive seal with the under surface of the column base plate 36 when pressed together. Port 32 communicates with a port 33 communicant with the inside of the hollow enclosed column or post 14. This post acts as a reservoir for the gas, in a manner to be described hereinafter.

Another port 40 in plate 26 is surrounded by a sealing O-ring 42 adapted to contact and seal against the under surface of column plate 36, and communicating with port 46, to flexible hose 48 that extends to plunger subassembly 18 (FIGS. 1 and 2).

Another opening 50 extends through plate 26 at the outer end of the plate. This orifice is intersected transversely by a blade latch 54 having a handle 56 on one end and a pivot mount 58 to plate 26 on the other end. This blade latch tits within a slot 60 in the outer extending end of plate 26. It is normally retained by spring 62 in a position to intersect the diameter of the through opening 50, as illustrated in FIG. 6.

The base 36 of support column 14 releasably interiits with mounting plate 26 by having its inner edge 36 slidably received beneath the overlying flange 66, This liange is part of a support block that is affixed to plate 26 along its inner edge. It extends upwardly and out over the edge of the plate 36. Alignment of plate 36 with plate 26 is facilitated adjacent flange 66 by a pair of straddling alignment pins 65. Attached to the opposite end of column base plate 36 is a tapered catch 70 having a narrow neck portion 72 between the enlarged head thereof and plate 36, into which latch blade 54 is biased to retain the assembly in tightly tting condition once it is assembled. This catch is mounted to plate 36 by a suitable stud and nut 74 connection. The support cylinder can be readily connected or disconnected, with the gas line connections being automatically completed with latching of the unit. Operational forces will not be applied to the latch, but only to the retention tiange 66 which is rigid and securely attached.

Secured to support column 14 is the compression arm 16, which extends radially therefrom, This compression arm includes a peripheral collar 80 that surrounds the column 14. This collar is rotatable on the post 14 and is vertically slidable when locking means 82 (FIG. 4) loosened. This locking means includes a pair of generally cylindrical abutting elements 84 and 86 on threaded stud 88. A knurled knob 90 is attached to one end of this stud for manual loosening and tightening. Elements 84 and 86 have tapered faces 92 and 94, respectively, adjacent to and abutting the periphery of post 14 to bind the assembly. The passage in element 86 is Unthreaded and forms a slip tit with stud 88. Passage 85 in element 84 is threaded to receive threaded stud 88. To bind the assembly, knob 90 is rotated so that its integral `collar 91 presses element 86 toward post 14 while threaded stud 88 simultaneously draws element 84 toward the opposite side of post 14 to bind on it. Once this binding connection is made, compression arm 16 is fixed vertically and rotationally with respect to the support column.

Mounted to the outer radial end of compression arm 16 is plunger subassembly 18. This includes a basic cylinder housing 100 (FIG. 3) having a gas line fitting connection 102, into which fitting 104 (FIG. l) from hose 48 interfits, to supply the upper end of the cylinder with compressed gas. The lower portion of the cylinder includes a cylindrical bushing 108, preferably of a lubricious material` such as nylon or Teon. The bushing is integrally attached to an annular plate 114 abutting the bottom face of cylinder 100 (FIG. 3). This plate as well as the retaining cap 110 and a lubricating wiper 116 are secured to the bottom annular face of cylinder 100 by suitable screws 112.

The plunger element 120 is preferably basically hollow in conliguration, having an enclosing upper end cap 122 inside cylinder 100. This end cap has a peripheral edge which extends out beyond plunger 120 to abut with the upper edge of bushing 108 and limit the downward stroke of the assembly. The lower end of plunger 120 includes a chest contacting resilient pad 128 which is adapted to abut the lower portion of the patients sternum in a manner to be described hereinafter.

Inscribed around and into the periphery of plunger 120 are spaced rings 121 of small indicia marks arranged in annuli. These are clearly visible to the operator as the plunger reciprocates vertically. The small vertical dimension of the small marks prevents the mark from being entirely concealed inside the cylinder when the plunger stops at the particular mark ring. The alignment of any one mark with the bottom face of cylinder 100 is indicative of piston extension and, therefore, of the depth of compression of the patients chest. Normally, these markings are placed approximately at one-half inch intervals, so that heavier rings 121 and 121 are at intervals of one and one-half inches. This is the normal deflection required for the average adult chest. The stroke length of the plunger 4 can be regulated accurately by watching these indicia as the regulatory valve knob 140 (FIG. 2) is rotated during operation.

Pneumatically operated valve assembly 22, preferably employed to allow pneumatic control of the timing of the pneumatically powered operation of the cardiac compressor, may be of the type described in detail in my above identified application. The system is supplied by pressurized gas, for example, from a conventional pressurized oxygen tank (not shown). Pressurized gas is supplied through a hose 144 (FIG. l) that connects to the releasable coupling 30, and thence to the pneumaticA supply and control means 22 (FIG. 6'), This is in communication with the reservoir 14 inside column 14 through hose 144 and ports 32 and 38, and is in communication with hose 48 through pressure regulator 154, hose 41, and ports 40 and 46. Pressure gauge 141 communicates with hose 41 downstream of regulator 154.

As indicated previously, the optimum amount of compression applied to the chest, and specifically the breastbone, of a particular patient to compress the heart will vary substantially depending largely upon the chest size of the patient. Extensive research has shown that the crucial factor is the anterior-posterior diameter (known medically as the A-P diameter) of the patients chest. This is the diameter from the breastbone to the backbone. It has been found that a stroke of approximately one-fifth or twenty percent of the chest A-P diameter is normally the optimum amount. This novel construction enables a particular selected compressive stroke to be accurately obtained from the reciprocating plunger, as visually determined by the human operator in a simple, effective manner using the device itself.

Specifically, at any particular vertical position of support arm 16 and its peripheral mount collar 80 on and around cylindrical post or column 14, the cooperative relation of the collar edge to column indicia 15 reflects the optimum stroke to be employed. These indicia markings, extending at least partially around the circumferential extent of the column, are preferably calibrated in terms of the plunger stroke length to be applied. This automatically indicates the optimum stroke length in relation to the particular A-P chest diameter of the patient on the platform. When the patient is lying on platform 12, vertical adjustment of arm 16 is made by turning knob 90 to loosen the clamp, vertically sliding collar and support arm 16 down until pad 128 is against the breastbone with plunger 120 pushed to its uppermost position inside its cylinder. Knob is tightened, to tighten the collar and arm on the post. The upper edge of collar 80 and indicia means 15 on the post will then cooperatively indicate the particular stroke which should be employed. As compressed oxygen is intermittently supplied to the piston plunger through its cylinder, the plunger will be extended out of the piston a controlled amount by adjusting pressure regulator 154 with its knob 140.

Alternatively, if the type of post in FIG. 8 with its special force markings is employed, the particular force indicated at the upper edge of collar 80a on cylinder 14a is the force which should be intermittently applied to the plunger cylinder iby adjusting regulator 154 and checking the force on force gauge 141.

Operation Assuming that patient P (FIG. 1) requires cardiac compressive treatment on an emergency basis, he is placed into the operative relation illustrated in FIG. l when the device is disassembled. That is, to detach the upper end of the unit, column 14 of the unit is grasped, and knob 56 is pulled to release the latch when blade 54 is moved to the phantom position illustrated in FIG. 5 against the bias of spring 62. This enables the column to be tilted forwardly to the position illustrated in FIG. 5 and FIG. 6, so that edge 36 of plate 36 can be slid backwardly, out from beneath hold down iiange 66. The column, compressive arm, and plunger are then laid aside for a moment while the base platform is inserted under the patient. The patient is first tilted by grasping his shoulder and rolling him part'way onto his side, so that -base platform 12 can be slid beneath his back. He is then rolled l'back to be flat on the platform. The column is replaced by inserting edge 36 again under ange 66, tilting the column vertically up to upright position so that knob 70 is inserted in opening S0 to catch beneath blade 54. This not only latches the assembly together, but also seals the passage connections at the ports illustrated in FIG. 5 due to the pressure of the O-rings against the underside of plate 36.

The plunger pad 128 is adjusted relative to the patient to lie over the lower part of his breastbone, ie. sternum. The exact position is achieved by loosening knob 90 and rotating arm 16 to assume its proper location. This is important for reasons stated previously.

Simultaneously, while arm 16 is movable on column 14, the arm is slid down until pad 128 contacts the chest when the pad and plunger are in the uppermost raised position (FIG. 1).

Then, gas supply hose 144, as from a conventional oxygen tank, is connected by coupling 30 to the system, to supply pressurized air. This is done when knob 140 (FIG. 2) is in closed position to prevent premature -air ow. No pressure then registers on gauge 141. The pressurized gas, when applied will act as the -actuating means for the plunger and will operate the timing controller 22 for the plunger. Plunger 120 is initially not pressurized, therefore, and can be held up in its upper retracted position illustrated in FIG. 1. Normally, its weight allows it to slide to its lowered position (FIG. 2), but it can be easily pushed up.

Air ow through line 144 will build up in reservoir chamber 14 in column 14 to act as a buffer and provide a constant, fairly steady pressure supply, even though the oxygen is supplied through a small hose from its tank.

This air supply is allowed to pass from reservoir 14 with controlled opening of regulator 154 by turning knob 149. This air will apply operating pressure, controlled by regulator 154 through knob 140 (FIG. 2) to the plunger cylinder to reciprocate the plunger. The timing of the reciprocation can be automatically controlled or manually controlled by reversing the gas dow to and from the plunger cylinder. This may be done with the preferred reciprocating spool valve disclosed in detail in my above identified patent application, or with some alternative control valve.

As soon as the arm 16 is vertically set with respect to the particular patient, the operator glances at the indicia markings 15 to see which one is closest to the collar 80. He then slowly opens the pressure regulator as the plunger reciprocates until the stroke of the plunger matches that indicated, or alternatively, until the force applied matches that indicated. By turning and thereby controlling force knob 149 (FIG. 2) to regulator 154, the amount that the plunger is repeatedly forced down against the breastbone to compress the chest and squeeze the heart is determined. This will vary with the size of the patient.

Several additional advantages will probably occur to those in the art upon studying the foregoing description of the preferred device. Also, it is conceivable that certain minor details of structure could be changed Within the concept presented, without departing from the invention as taught. Therefore, the invention is t0 be limited only 'by the scope of the appended claims and the reasonably equivalent structures to those dened therein.

I claim:

1. An external type cardiac compressor comprising: a platform; a compressor spaced above said platform and reciprocable toward and away from said platform; compressor support means between said platform and compressor to maintain them in selected spaced relation; said support means having at least two interftting components including lockable adjustment means therebetween allowing variable spacing of said compressor to said platform to accommodate different anterior-posterior chest diameters; and graduated, cooperative, compressor-stroke indicia means between said interlitting components graduated to indicate the compressor stroke to be employed for a particular chest diameter spacing of said compressor with respect to said platform.

2. A cardiac compressor comprising: a base having a patient support platform; an upright support column extending up from said base alongside said platform; a compressor support -arm extending laterally from said column over said platform; reciprocable compressor means on said arm, reciprocable toward and away from said platform; said support arm @being adjustable on said column toward and away from said platform; and cooperative, indicia means between said support arm and said column, graduated to indicate the extent of compression to -be applied "by said compressor means in relation to the position of said arm with respect to said platform.

3. A cardiac compressor comprising: a base including a support platform for a patients back; 4a support column extending transversely from said platform alongside thereof; a compressor arm extending radially from said column and terminating in a uid receiving cylinder over said platform and oriented toward said platform; a chest compressing, fluid operated piston plunger extending from said cylinder and reciprocable therein toward and away from said platform to be loperable on a chest; said arm including connector means to said column, with releasable locking means therebetween, enabling movement of said arm, cylinder and plunger toward and away from said platform to accommodate different anteriorposterior chest diameters; and compressor-stroke indicia means cooperative with said arm and graduated to indicate the proper plunger reciprocation stroke in relation to a particular A-P chest diameter spacing said platform and said plunger.

4. A cardiac compressor comprising: a base including a support platform for a patients back; a support column extending transversely up from said platform alongside thereof; a compressor arm extending radially from said column and terminating in a fluid receiving cylinder over and oriented toward said platform; a chest compressing, uid operated piston plunger extending from said ycylinder and reciprocable therein toward yand away from said platform to be operable on a chest; said arm including a connector to said column, with releasable locking means therebetween, enabling movement of said arm, cylinder and plunger toward and away from said platform to accommodate different anterior-posterior chest diameters; and indicia means ybetween said arm and column graduated in relation to the spacing of said plunger with respect to said platform to accommodate different anteriorposterior chest diameters, to thereby enable optimum plunger stroke for a particular chest diameter.

5. A cardiac compressor comprising: a base including a support platform for a patients back; a support column extending transversely up from said platform alongside thereof; a compressor arm extending radially from said column and terminating in a fluid receiving cylinder over and oriented toward said platform; a chest compressing, fluid operated piston plunger extending from said cylinder and reciprocable therein toward and away from said platform to be operable on a chest; said arm including a connector to said column, `with releasable locking means therebetween, enabling movement of said arm, cylinder and plunger toward and away from said platform to accommodate different anterior-posterior chest diameters; plunger stroke indicia means between said arm and column graduated in relation to spacing of said plunger with respect to said platform and indicative of plunger Stroke to accommodate different anterior-posterior chest diameters, to thereby enable optimum plunger stroke for a particular chest diameter; and graduated lplunger stroke indicia means between said plunger and cylinder to allow correlation thereof with said first mentioned indicia means.

6. An external type cardiac compressor comprising: a platform; a Compressor spaced above said platform and reciprocable toward and awa;I from said platform; power reciprocation means for said compressor, including adjustable reciprocation stroke length control means; compressor support means between said platform and compressor to maintain them in selected spaced relation; said support means having at least two intertting components including lockable adjustment means therebetween allowing variable spacing of said compressor to said platform to accommodate different anterior-posterior chest diameters; graduated cooperative -compressor-stroke indicia means between said intertting components adapted to indicate the compressor stroke to be employed for a yselected spacing of said compressor with respect to said platform to accommodate a particular chest diameter; and graduated indicia means between said compressor and said support means to indicate actual compressor stroke being applied.

7. A cardiac compressor comprising: a base including a support platform for a patients back; a `support column extending transversely up from said platform alongside thereof; a compressor arm extending radially from said column and terminating in a uid receiving cylinder over and oriented toward said platform; a chest compressing,

uid operated piston plunger extending from said cylinder and reciprocable therein toward and away from said platform to be operable on a chest; operating fluid `supply means to said cylinder, and How control means therefor to regulate plunger stroke; said arm including a connector to said column, with releasable locking means therebetween, enabling movement of said arm, cylinder and plunger toward and away from said platform to accommodate different `anterior-posterior chest diameters; graduated compressor-stroke indicia means to indicate a plunger stroke characteristic; and indicia means between said arm and ycolumn graduated in relation to spacing of said plunger with respect to said platform and indicating the optimum plunger stroke characteristic for particular chest diameters.

8. The compressor in claim 3 wherein 'said indicia means is calibrated in terms of force to be applied to the chest.

9. The compressor in claim 3 wherein said indicia means is calibrated in terms of stroke length of said compressor.

References Cited UNITED STATES PATENTS 3,219,031 ll/l965 Rentsch 128-51 3,234,934 2/1966 Woodward 128-53 3,254,645 6/1966 Rand et al 128-52 L. W. TRAPP, Primary Examiner. 

4. A CARDIAC COMPRESSOR COMPRISING: A BASE INCLUDING A SUPPORT PLATFORM FOR A PATIENT''S BACK; A SUPPORT COLUMN EXTENDING TRANSVERSELY UP FROM SAID PLATFORM ALONGSIDE THEREOF; A COMPRESSOR ARM EXTENDING RADIALLY FROM SAID COLUMN AND TERMINATING IN A FLUID RECEIVING CYLINDER OVER AND ORIENTED TOWARD SAID PLATFORM; A CHEST COMPRESSING, FLUID OPERATED PISTON PLUNGER EXTENDING FROM SAID CYLINDER AND RECIPROCABLE THEREIN TOWARD AND AWAY FROM SAID PLATFORM TO BE OPERABLE ON A CHEST; SAID ARM INCLUDING A CONNECTOR TO SAID COLUMN, WITH RELEASABLE LOCKING MEANS THEREBETWEEN, ENABLING MOVEMENT OF SIAD ARM, CYLINDER AND PLUNGER TOWARD AND AWAY FROM SAID PLATFORM TO ACCOMMODATE DIFFERENT ANTERIOR-POSTERIOR CHEST DIAMETERS; AND INDICIA MEANS BETWEEN SAID ARM AND COLUMN GRADUATED IN RELATION TO THE SPACING OF SAID PLUNGER WITH RESPECT TO SAID PLATFORM TO ACCOMMODATE DIFFERENT ANTERIORPOSTERIOR CHEST DIAMETERS, TO THEREBY ENABLE OPTIMUM PLUNGER STROKE FOR A PARTICULAR CHEST DIAMETER. 